SINGLE A MINOR LEAGUE SYSTEMS (Past and Present):

SINGLE A (Advanced)

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California League
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Carolina League
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Florida State League

SINGLE A (Full Season)
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Midwest League
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South Atlantic League

SINGLE A (Short Season)

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New York Penn League
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Northwest League

ROOKIE:
- Appalachian League
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Pioneer League

DEFUNCT CLASSIFICATIONS:

DEFUNCT SINGLE A:
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Alabama Florida League aka Alabama State League (Defunct: 1939-1962)
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Northern League (Defunct: 1946-1970) *See Single-A

CLASS B:
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Quebec Provincial League (Defunct: 1940)
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Triple-I League (Illinois-Iowa Indiana League) (Defunct: 1919-1961)

CLASS C:
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Colonial League (Defunct: 1947-1950)

CLASS D:
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Kitty League (Defunct: 1946-1955)
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KOM League (Defunct: 1946-1952)
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North Atlantic League (Defunct: 1946-1950)









Affiliated Single-A Minor League Baseball